Outspoken Philippine President Rodrigo Duterte lashed out at US President Barack Obama again on Tuesday, telling the American leader to "go to hell" and threatening to buy weapons from Russia and China. His comments came as the two countries began their routine joint military exercises - for what Duterte has claimed will be the last time.

In a series of speeches made throughout the day in Manila, Duterte said it was his "sacred duty" to uphold the integrity of the Philippines and keep its people healthy.

Duterte said the United States should have supported the Philippines in tackling its chronic drugs problems but that instead it had criticized him for the high death toll, as did the European Union.

"Instead of helping us, the first to hit was the State Department. So you can go to hell, Mr Obama, you can go to hell," he said.

He also said his nation would purchase weapons from Russia and China.

"If you don't want to sell arms, I'll go to Russia. I sent the generals to Russia and Russia said everything you need, we'll give it to you'…. And as for China, they said 'just come over and sign and everything will be delivered.'"

He referred to his new anti-US stance as a "breakup" between Manila and Washington.

Duterte is no stranger to incendiary rhetoric; he recently called the US president a "son of a whore" before backtracking.

The White House has downplayed the incident.

Press Secretary Josh Earnest said the Philippine president's rhetoric was "at odds with the warm relationship that exists between the Filipino and American people," and that there has been no official move from Manila to change the nature of the two nations' bilateral ties.

Duterte later said he had told Obama to "go to hell" because he was emotional at the lack of support he has gotten for his bloody war on drug trafficking, which has resulted in over 2,000 deaths.

es/bw (dpa, Reuters)